When a Canvas content template uses the sdc.morphos.content component with an entity-field prop source pointing to a text_long:processed field (e.g. entity:node:mc_article:field_mc_content:processed), all #attached CSS/JS libraries added by text filters are silently discarded. More info can be found in the issue https://www.drupal.org/project/highlight_js/issues/3584177#comment-16600243 Also there is core related issue https://www.drupal.org/project/drupal/issues/3280235